/// <summary>
/// Get the axis-aligned <see cref="BoundingBox"/> which contains all <see cref="OrientedBoundingBox"/> corners.
/// </summary>
/// <returns>The axis-aligned BoundingBox of this OrientedBoundingBox.</returns>
public BoundingBox GetBoundingBox()
{
return(BoundingBox.FromPoints(GetCorners()));
}
/// <summary>
/// Check the intersection between an <see cref="OrientedBoundingBox"/> and <see cref="BoundingBox"/>
/// </summary>
/// <param name="box">The BoundingBox to test.</param>
/// <returns>The type of containment the two objects have.</returns>
/// <remarks>
/// For accuracy, The transformation matrix for the <see cref="OrientedBoundingBox"/> must not have any scaling applied to it.
/// Anyway, scaling using Scale method will keep this method accurate.
/// </remarks>
public ContainmentType Contains(ref BoundingBox box)
{
var cornersCheck = Contains(box.GetCorners());
if (cornersCheck != ContainmentType.Disjoint)
{
return(cornersCheck);
}
var boxCenter = box.Minimum + (box.Maximum - box.Minimum) / 2f;
var boxExtents = box.Maximum - boxCenter;
var SizeA = Extents;
var SizeB = boxExtents;
var RotA = GetRows(ref Transformation);
float ExtentA, ExtentB, Separation;
int i, k;
Matrix.Invert(ref Transformation, out var R);
var AR = new Matrix(); // absolute values of R matrix, to use with box extents
for (i = 0; i < 3; i++)
{
for (k = 0; k < 3; k++)
{
AR[i, k] = Math.Abs(R[i, k]);
}
}
// Vector separating the centers of Box B and of Box A
var vSepWS = boxCenter - Center;
// Rotated into Box A's coordinates
var vSepA = new Vector3(Vector3.Dot(vSepWS, RotA[0]), Vector3.Dot(vSepWS, RotA[1]), Vector3.Dot(vSepWS, RotA[2]));
// Test if any of A's basis vectors separate the box
for (i = 0; i < 3; i++)
{
ExtentA = SizeA[i];
ExtentB = Vector3.Dot(SizeB, new Vector3(AR[i, 0], AR[i, 1], AR[i, 2]));
Separation = Math.Abs(vSepA[i]);
if (Separation > ExtentA + ExtentB)
{
return(ContainmentType.Disjoint);
}
}
// Test if any of B's basis vectors separate the box
for (k = 0; k < 3; k++)
{
ExtentA = Vector3.Dot(SizeA, new Vector3(AR[0, k], AR[1, k], AR[2, k]));
ExtentB = SizeB[k];
Separation = Math.Abs(Vector3.Dot(vSepA, new Vector3(R[0, k], R[1, k], R[2, k])));
if (Separation > ExtentA + ExtentB)
{
return(ContainmentType.Disjoint);
}
}
// Now test Cross Products of each basis vector combination ( A[i], B[k] )
for (i = 0; i < 3; i++)
{
for (k = 0; k < 3; k++)
{
int i1 = (i + 1) % 3, i2 = (i + 2) % 3;
int k1 = (k + 1) % 3, k2 = (k + 2) % 3;
ExtentA = SizeA[i1] * AR[i2, k] + SizeA[i2] * AR[i1, k];
ExtentB = SizeB[k1] * AR[i, k2] + SizeB[k2] * AR[i, k1];
Separation = Math.Abs(vSepA[i2] * R[i1, k] - vSepA[i1] * R[i2, k]);
if (Separation > ExtentA + ExtentB)
{
return(ContainmentType.Disjoint);
}
}
}
// No separating axis found, the boxes overlap
return(ContainmentType.Intersects);
}
